1. IN THE TANK

    Dirty Aquariums Make Fish Angry

    Yellow Tang, saltwater tropical fish collected in the waters off the West Hawaii coast and popular with aquarium owners, swim in a tank at a retail tropical fish store in Culver City, Calif., Thursday, Feb. 12, 1998. The Hawaii legislature decided on  Thursday, Feb. 12, 1998, on tighter management controls over the collection of tropical fish around the islands as diminished fish populations have been detrimental to the state's SCUBA and snorkeling businesses. (AP Photo/Nick Ut)

    Nick Ut, File / AP Photo

    There’s danger in the water, and it involves ornamental fish. Dirty aquariums can lead to killer fish, says a new study. Although, it’s likely that most ornamental fish are already livid and violent. How can you tell that a fish is mad? In the study, mild-mannered fish flared their fins, while ticked-off fish killed each other. Ronald Oldfield, a biology instructor at Case Western Reserve University, thinks it may show insight into human action. "This study might help us to better understand how human behavior changes when people are placed in different social environments," he said.

    Read it at Discovery News